Ignition means for reaction motors used in connection with missiles



Jan. 15, 1963 KIRSCH 3,073,994

W. IGNITION MEANS FOR REACTION MOTORS USED IN CONNECTION WITH MISSILES Filed NOV- 16, 1959 INVENTOR Wilhelm Kirsch ATTORNEYS 3,73,994 Patented Jan. 15, 1963 3,0733% IGNETIUN MEAN F03 REArCTlGN MTOR IN CQNNECTEQN iilTR-ll MESSELES Wilhelm Kirsch, Ottohrunn, near Munich, Germany, as-

signor to BolknW-Entwichinngen KG, @ttohrunn, near Munich, Germany Filed Nov. 16, 1959, Ser. No. 853.3% Claims priority, application Germany Nov. 22, 1953 2 Claims. (Cl. 317--79) The present invention relates, in general, to electric ignition means or devices for reaction motors and in particular concerns recoil type mechanisms having a starting motor and an operating motor rigidly connected to a missile of the remote control type.

Such ignition devices have to meet an extremely high standard. For example, the ignition devices must function properly even when the missile motors are started suddenly, after years of storage, at extremely high or extremely low external temperatures. In addition, rough handling and vibrations of the missile must not result in the start of its motors since this may cause serious accidents.

Furthermore, the ignition means should occupy a minimum amount of space and should be capable of starting the missile motors within a fraction of a second. if the starting motor should fail, neither the operating or running motor, nor the flare means connected in parallel therewith must suddenly start to burn since this usually leads to the destruction of the missile.

It is an object of the present invention to provide means obviating the previously stated dangers and other disadvantages.

It is another object of the present invention to provide means contributing to a safe and reliable electric ignition device for starting reaction drive motors.

It is a further object of the invention to provide means efiectuating the start of the running or operating motor only after a successful start of the missile.

The above and other objects of the invention will become further apparent from the following detailed description, reference being made to the accompanying drawing showing a preferred embodiment of the invention.

In the drawing which illustrates the best mode presently contemplated for carrying out the invention, the sole FIGURE is a schematic wiring diagram of an electric ignition means pursuant to the present invention.

Pursuant to the present invention a temperature-resistant and age-resistant ignition condenser of low capacity, used for igniting the operating or running motor of the missile, is provided in its charging circuit with a transistor in a coresonant connection. The condenser is interrupted in its ignition circuit by the operating contact of an acceleration-responsive switch in such a manner that an ignition pulse starts the operating motor only after a successful start of the missile. Otherwise the ignition pulse is conducted across the blocking resistance of the charging rectifier. By suitably dimensioning the switch elements, the desired delayed ignition of the operating or running motor may be achieved in a relatively simple manner. A low battery voltage is utilized to ignite both motors, so that relatively simple and portable controls can be utilized. Despite the omission of eleients which respond to temperature and aging, for example, electrolytic condcnser, the ignition voltage is sufficiently high for ignition purposes. If the starting motor fails to ignite, the missile can be examined after a relatively short time without fear of an accidental start of one of the motors.

Referring now to the drawing in detail, there is shown an ignition circuit 29, pursuant to the invention. Said circuit includes a transformer 1 which, for example and not by way of limitation, is of the pot core coil type. The primary winding la has one end connected via line 21 to the positive terminal 2 of a DC. voltage supply. The other end of said winding is connected by line 22, series resistors R1 and R2 and line 23 to the negative terminal 2 of said D.C. supply. Resistance R1 is preferably 90 ohms and R2 is preferably ohms. The base 3 of transistor 24 is connected between the two resistors. The emitter 5 of said transistor is connected to the center top 6 of winding 1a. The collector 4 of the transistor is connected to negative terminal 2 by line 23. An ignition wire or igniter 7 for the reaction start motor means 3 is connected across terminals 2 in parallel with the primary winding In. It will be understood that transformer 1 and transistor 24 form a DC. converter.

The secondary circuit of the converter includes the secondary winding 1b of the transformer, an ignition condenser C1 connected across the secondary winding and a rectifier 9 connected between one end of the secondary winding and condenser C1.

The capacity of the latter is preferably in the range of 0.5 to l microfarad. Line 10, in which the rectifier is connected, extends to the stationary operating or main contact 11 of an acceleration-responsive switch 12. The switch also includes a movable or inertial switch element 25 which is normally engaged with a stationary rest contact 13 to short-circuit the ignition wires or igniters 14 and 15 which are connected in parallel.

Igniter 14 serves to ignite the reaction running or operating motor means 16 of the missile. Igniter 15 serves to ignite the flare material 17. The parameters of the DC. converter are such that the time constant for charging the ignition condenser C1 is about one third of the duration time of the external ignition pulse.

If a DC. voltage having a magnitude, for example and not by way of limitation, in the range of 6 to 12 volts, is applied to terminals 2, the igniter 7 is energized and ignites the starting motor means 8. At the same time, the DC. converter constituted by transformer 1 and transistor 24 is energized to provide a highly stepped-up AC. voltage. The stepped-up voltage is rectified by rectifier 9 and charges the ignition condenser C1.

In the meantime, the missile has been started by the reaction starting motor means 8. When a predetermined acceleration thereof has been attained, the movable or inertial switch element 25 of the acceleration-responsive switch 12 disengages contact 13 and engages the operating contact 11. This removes the short-circuit from the igniters l4 and 15 and connects the common point 26 thereof with condenser C1. The latter now discharges through line It engaged contacts 11-25 and line 18 to energize the igniters 14 and 15. lgniter l4 ignites the reaction running or operating motor means 16 of the missile and igniter 15 ignites the flare material 17. The voltage of the ignition pulse generated by discharge of condenser C1 is, for example and not by way of limitation, 200 volts.

If the starting motor means 8 fails to ignite, the acceleration-responsive switch 12 remains in its initial starting condition, as illustrated, so that lines 1t} and 18 are disconnected from each other. Condenser C1 can now discharge over the blocking resistance of rectifier 9 without igniting the running motor means 16 or the flare medium 17. if required in order to facilitate such discharge of the condenser, a resistor R3 can be connected in parallel therewith.

The ignition circuit 2-!) will function properly at temperatures as low as 30 degrees below zero centigrade and even after more than 10 years in storage.

Various changes and modifications may be made without departing from the spirit and scope of the present invention and it is intended that such changes and modificatio'ns be embraced by the annexed claims.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. Electric ignition system for starting and running reaction motors of a missile comprising a relatively low capacity ignition condenser for providing an ignition pulse for the running motor, converter means for charging said condenser, a normally interrupted ignition circuit between said condenser and said running motor, and accelerationresponsive means operable to close said ignition circuit upon attainment of a predetermined acceleration by said missile, said converter means including converter, a transformer and a transistor in coresonant connection with the primary winding of said transformer, said condenser being connected across the secondary Winding of said transformer, and an igniter for said starting motor connected in parallel with said converter.

2. Electric ignition system for starting and running reaction motors of a missile comprising a relatively low capacity ignition condenser for providing an ignition pulse for the running motor, converter means for charging said condenser, a normally interrupted ignition circuit between sa-id'condenser and said running motor, and accelerationresponsive means operable to close said ignition circuit upon attainment of a predetermined acceleration by said missile, wherein the charging means comprises a DC. converter, constituted by a transistor in coresonant connection with the primary winding of a transformer, said condenser being connected across the secondary'winding of said transformer, and an igniter for said starting motor connected in parallel with said converter, an additional igniter for said running motor, said accelerationresponsive means comprising a switch operable to normally short circuit said running motor igniter and upon attainment of a predetermined acceleration to connect said condenser to said running motor igniter.

i tet'erences Cited in the file of this patent UNITED STATES PATENTS 

1. ELECTRIC IGNITION SYSTEM FOR STARTING AND RUNNING REACTION MOTORS OF A MISSILE COMPRISING A RELATIVELY LOW CAPACITY IGNITION CONDENSER FOR PROVIDING AN IGNITION PULSE FOR THE RUNNING MOTOR, CONVERTER MEANS FOR CHARGING SAID CONDENSER, A NORMALLY INTERRUPTED IGNITION CIRCUIT BETWEEN SAID CONDENSER AND SAID RUNNING MOTOR, AND ACCELERATIONRESPONSIVE MEANS OPERABLE TO CLOSE SAID IGNITION CIRCUIT UPON ATTAINMENT OF A PREDETERMINED ACCELERATION BY SAID MISSILE, SAID CONVERTER MEANS INCLUDING CONVERTER, A TRANSFORMER AND A TRANSISTOR IN CORESONANT CONNECTION WITH THE PRIMARY WINDING OF SAID TRANSFORMER, SAID CONDENSER BEING CONNECTED ACROSS THE SECONDARY WINDING OF SAID TRANSFORMER, AND AN IGNITER FOR SAID STARTING MOTOR CONNECTED IN PARALLEL WITH SAID CONVERTER. 